Redox equations are often long and difficult to balance by inspection. Luckily, electron transfers and oxidation numbers provide hints for balancing such equations. Balance the following equation:

K2CrO4 + Na2SO3 + HCl ---> KCl + Na2SO4 + CrCl3 + H20

1 answer

I'll help you get started but I shall be happy to explain anything you don't understand.
Cr changes oxidation state from +6 on the left to +3 on the right.
S changes oxidation state from +4 on the left to +6 on the right.